In seats, especially in car seats, it is desirable not only to perform basic adjustments such as the inclination of the backrest or seat cushions or the seat height. Rather, the aim is to also design the seat contour or firmness of the upholstery in an adjustable way so the seat can be adapted to the anatomical conditions of the various seat users or to increase the seat comfort. To achieve this, it is typical to integrate an adjustable lumbar support into the backrest, for example. To enhance the well-being of a seat user and prevent a driver's tiredness and stress, for example, massaging systems integrated into the seat can also be used. Moreover, the side bolsters of the seat are often adjustable as well in order to adapt the backrest or seat cushion width to the body structure of the respective seat user to offer secure lateral support.
Such lumbar support or such massaging system or such side bolster adjustment is made possible by one or several bubbles or air cushions built into the seat that are generally made of an elastic material that can be filled with air or emptied or deflated. The inflating and deflating of the air cushions is typically accomplished with the help of valves and a pneumatic pump. The quantity of the air filling the air cushions affects their firmness or shape and therefore the seat's contour. As a result of this, the lumbar support and/or lateral support can be adapted to the individual seating needs of the respective user and then maintained while the seat is being used, which is the case while the car is being driven, for example. To execute a massaging function, the air cushions integrated into the seat are cyclically filled and deflated, thereby changing the contour of the seat selectively and dynamically.
In current massaging systems or lumbar supports or for adjusting the lateral support, the air cushions are integrated into the seat in such a way that they are placed directly on the structural elements of the seat structure; in the case of a massaging system or lumbar support, for example, on the seat cushion or backrest cushion, which are typically made of foam. In the side bolster, the air cushions rest, for example, directly on so-called supporting plates, integrated into the side bolsters of the seat as part of the seat structure. If one or several of the air cushions are filled, they sink into the seat cushion or backrest cushion while being inflated, since the foam does not offer enough counter support and the air cushion therefore expands uniformly in all directions. Consequently, the desired effect is not fully achieved. For example, a change in the seat's contour while the lumbar support is being adjusted is noticeable only after some time, as soon as the air cushion has already been partially filled with air and not already at the start of filling process. When the massaging function is being performed, a massaging effect is not sufficiently noticeable, for example. Faster reactions are also desirable when adjusting the side bolsters, even if in this case a sinking of the air cushion is already largely ruled out owing to the hardly existing cushioning or lack thereof.
Therefore, to compensate for this effect, larger air cushions or larger air supply units are used to achieve a sufficient massaging effect or to adjust the lumbar support or lateral support faster. However, larger air cushions in turn also mean a longer running time of the pump to fill them with the same pressure, thereby possibly reducing the operating life of the supply lines, valves and the pump itself. An overall larger air supply unit is also disadvantageous, as there is only little available space inside a seat, especially a car seat, and also the weight of the massaging system or lumbar support or side bolster adjustment should be maintained as low as possible.